Device for multimeasurement of vertical position variation and a level-setting system equipped with said device

ABSTRACT

A device for multimeasurement of vertical position variation of one or a number of predetermined points of an industrial or scientific construction of installation comprises means for measuring pressure which appears at the locations of these points and the variation of which is directly related to a variation in level of said points.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a device for multimeasurement ofvertical position variation and to a level-setting system equipped witha device of this type.

2. Description of the Prior Art

A measurement of vertical variation in position of one or a number ofpredetermined points of an industrial or scientific construction orinstallation, which makes it possible to follow a change in level ofthese points, often proves essential for good maintenance of saidconstruction or installation. In fact, good operation of a structuresuch as a dam or an industrial or scientific installation such as asynchrotron is largely dependent on relative stability of its differentparts. In point of fact, a construction or installation of this typeoften extends over a large land area whose structure, composition andhydrographic state may change from one location to another and causeunequal sliding of its strata or heterogeneous land subsidence whichdisturbs the operation or impairs the strength or good operation of theconstruction or installation considered. In a scientific installationsuch as that of a synchrotron, a variation in level by a value ofone-tenth of a millimeter can already have an adverse effect on itsoperation or industrial or scientific exploitation. In order to overcomethis drawback, some thought has been given to the possibility ofcontrolling the variation in level of the principal points of aninstallation of this type by laser sighting. However, these points areoften remote from each other or concealed with respect to each other. Inorder to obtain rapidly or at any moment data relating to the variationin level of these points, each point has to be equipped with a laseremitter and with an associated receiver. Equipment of this type entailsthe need for substantial capital outlay.

The present invention aims to circumvent these disadvantages bypermitting the construction of an economical device for multimeasurementof vertical position variation which is capable of detecting variationsof small values of the order of one-tenth of a millimeter and of aneconomical and effective level-setting system equipped with a device ofthis type which is capable of carrying out in an industrial orscientific installation even a position adjustment of its principalpoints by a small value of the order of one-tenth of a millimeter.

SUMMARY OF THE INVENTION

In accordance with the invention a device for multimeasurement ofvertical position variation of one or a number of predetermined pointsof an industrial or scientific construction or installation essentiallycomprises means for measuring pressure which appears at the locations ofsaid points and the variation of which is directly related to avariation in level of said points.

A system for level-setting of one or a number of predetermined points ofan industrial or scientific installation such as that of a synchrotronequipped with a device for multimeasurement of vertical positionvariation of said points essentially comprises an assembly for levelcompensation involving dimensional change by thermal action, saidassembly being inserted between said point or points and its support ortheir supports.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a device constructed in accordance withthe invention for multi-measurement of vertical position variation.

FIG. 2 is a partial schematic view to a different scale showing thedevice of FIG. 1.

FIG. 3 is a partial schematic view to a different scale showing analternative embodiment of the device of FIG. 1.

FIG. 4 is a partial schematic view to a different scale showing alevel-setting system constructed in accordance with the invention andequipped with the device of FIG. 1 for multimeasurement of verticalposition variation.

FIG. 5 is a partial schematic view to a different scale showing anelectron synchrotron in which are mounted the vertical positionvariation multimeasurement device of FIG. 1 and the level-setting systemof FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A device for multimeasurement of vertical position variation constructedin accordance with the invention is applicable to measurement, tosurveillance or to control of level-setting of one or a number ofpredetermined points of an industrial or scientific construction orinstallation.

In accordance with an important feature, a device for multimeasurementof vertical variation in position of one or a number of predeterminedpoints comprises means for measuring pressure which appears at thelocations of said points and the variation of which is directly relatedto a variation in level of said points. Said device comprises means forconverting results of said measurement of pressure variation to resultsof linear measurement of variation in level of said points. And saidpoints are selected predetermined points which can be located very closetogether at distances of a few centimeters or very far apart atdistances of several hundred meters.

In one example of construction illustrated in FIG. 1, a device 1 formultimeasurement of vertical position variation of several predeterminedpoints 2, 3, 4, 5 comprises as pressure-measurement means on the onehand a tank 6 containing a liquid 7 and open to free air, a first tube 8attached respectively to said points 2, 3, 4, 5 and having two ends 11,12 in free communication with the tank 6 so as to be continuously filledwith said liquid 7, a second tube 14 filled with air and also attachedrespectively to said points 2, 3, 4, 5 and having two ends 15, 16 whichopen freely to the surrounding atmosphere in proximity to the tank 6containing liquid 7. The device further comprises pressure gages 18, 19,20, 21 of known type which are attached on one side to the lower portionof the wall of the tube 8 containing liquid 7 respectively at thelocations of the points 2, 3, 4, 5 and on the other side to the air tube14. The means for converting the results of said measurement consists ofan electronic apparatus 25 of known type (not described hereinafter) foramplifying and converting in known manner the electrical measurementdata emitted by said gages to data relating to linear measurement ofvariation in level of said points, and of recording and/or display ofsaid data.

When one point 2 of the points 2, 3, 4, 5 undergoes for example avariation in level dN (FIG. 2), the tube 8 containing liquid 7 andattached to said point follows its movement so that the height of columnof liquid 7 within the tube 8 with respect to the free surface 28 ofsaid liquid 7 within the tank 6 increases from h to H (h+dH=H), thusproducing a variation in height of liquid column 7 by a value dH,whereupon the pressure gage 18 corresponding to said point 2 measures avariation in pressure of dP. The pressure variation dP measured by thegage 18 is therefore directly related to the variation in level dN.

In consequence, the variations in pressure dP measured by the gages 18,19, 20, 21 accurately represent the variations in level dN of the points2, 3, 4, 5 and are directly converted to dN by the electronic apparatus25 for acquisition of measurement results.

In the example illustrated, the liquid 7 consists of mercury, theliquid-filled tube 8 has a selected diameter between 1 and 2 centimetersand the air-filled tube 14 has a selected diameter between 0.3centimeter and 10 centimeters.

The air tube 14 has ends which are located in proximity to the tank 6and open freely into the atmosphere. This arrangement makes it possibleto have a uniform reference atmospheric pressure at any point of saidtube 14 and consequently t employ economical pressure gages whichconform simply to a requirement of reliability of operation.

In a first alternative embodiment shown in FIG. 3, the device formultimeasurement of vertical position variation comprises the sameelements as those of the device illustrated in FIGS. 1 and 2 except forthe fact that the air tube 18 is dispensed with and the economicalpressure gages 18, 19, 20, 21 are replaced by more costly pressure gagesof the absolute type which must have good sensitivity and highprecision.

In a second alternative embodiment of the liquid-flow device illustratedin FIGS. 1 and 2, a liquid circulation pump 30 is mounted within thetube 8 in order to accelerate and to perfect a filling with liquid 7.

In a third alternative embodiment of the device for multimeasurement ofposition variation as illustrated partially and schematically in FIG. 3,the tank 6 containing liquid 7 is closed by a cover 32 and the ends 15and 16 of the air tube 14 have openings through said cover 32 above thefree surface 28 of the liquid 7.

The device for multimeasurement of vertical position variation asillustrated in FIGS. 1 and 2 advantageously makes it possible to performwith the same ease measurements of variation in level of thepredetermined selected points which are in direct view with respect toeach other and measurements of variation in level of the predeterminedselected points which are concealed with respect to each other. Thisgreat ease of measurement is not found in laser sighting systems alreadyrecalled in an earlier paragraph.

In accordance with the invention, a system for level-setting of one or anumber of predetermined points, equipped with a device formultimeasurement of vertical position variation which is described inthe foregoing and illustrated in FIGS. 1 to 3, comprises an assembly forlevel compensation involving dimensional change by thermal action, saidassembly being inserted between said point or points and its support ortheir supports.

In one example of construction which is partially and schematicallyillustrated in FIGS. 1 and 4, a system 35 for level-setting of thepoints 2, 3, 4, 5 comprises an assembly for level compensation withdimensional change by thermal action. Said assembly consists on the onehand of thermally expansible elements 36 such as metal rods, jacksoperating under the action of thermally expansible material and insertedrespectively between these points 2, 3, 4, 5 and their respectivesupports 37, and heating elements 38 associated with said expansibleelements 36. Said compensating assembly consists on the other hand of adevice 1 for multimeasurement of vertical position variation and acontrol relay 40 of known type which connects the heating elements 38 tothe corresponding outputs of the device 1 for multimeasurement ofposition variation or in other words to the outputs of its electronicapparatus 25 for acquisition of measurement results so as to providesaid heating elements with automatic individual supply adjusted inelectric power with a view to obtaining accurate automatic compensationof the variation in level of said points 2, 3, 4, 5 by means of saidexpansible elements 36 and restoring said points to the same plane whichcoincides with or is parallel to their initial plane and withoutinducing any mechanical vibration.

The expansible elements 36 and their associated heating elements 38 arepreferably heat-insulated with respect to the surrounding medium bymeans of heat-insulating walls 42 and mechanically isolated from thesupports 37 of said points 2, 3, 4, 5 by means of heat-insulatingelements and/or anti-vibration elements.

The device 1 for multimeasurement of vertical position variation and thelevel-setting system 35 are excellently applicable to the installationof a synchrotron 50 as illustrated partially and schematically in FIG.5.

The synchrotron 50 includes an electron-injecting device 51, asynchrotron ring 52 and a storage ring 53.

In the example illustrated, the synchrotron ring 52 has a diameter ofthe order of 150 meters and the storage ring 53 has a diameter of theorder of 270 meters. The storage ring 53 is usually formed by anend-to-end assembly of sections of straight tubes 55 and ofelectromagnets 56 at the level of their joints in order to bring thepath of a traveling electron continuously in the axis of said successivesections of straight tubes 55.

By means of said storage ring 53, an electron which is injected by thedevice 51 into the synchrotron ring 52 within which it attains asufficient velocity to be placed in the storage ring 53 is permitted toemit linear radiations 57 along the axis of the straight sections oftube 55 at the time of a change in direction of its path by means of theelectromagnets 56 as it passes from one of said straight tube sectionsto another. Said linear radiations 57 pass out of said storage ring 53and thus permit their industrial or scientific exploitation by anapparatus or receiver 60. In order to ensure correct operation of thesynchrotron 50 and the receiver 60, the positions of the injector device51 of the synchrotron ring 52 and storage ring 53 and of the receiver 60must be stable or, in other words, the axes of these latter must becontinuously located in the same plane. A variation in level of saiddevices 51, rings 52, 53 and apparatus 60 by a value of the orderone-tenth of a millimeter is sufficient to disturb their operation.

The position multimeasurement device 1 and the level-setting system 35described in the foregoing are capable of continuously bringing the axesof said devices 51, rings 52, 53 and apparatus 60 in the same planewhich can coincide with or be parallel to their initial plane, thusenabling the synchrotron 50 and its industrial or scientificinstallation to operate normally in spite of variations in level of saidelements caused, for example, by a landslide at the site location ofsaid synchrotron installation.

In the position multimeasurement device 1, the thermally expansibleelements 36 are equipped with thermal measurement means of known typewhich makes it possible to determine their dimensions.

What is claimed is:
 1. A device for multimeasurement of verticalposition variation of a number of predetermined points of an industrialor scientific construction or installation, wherein said devicecomprises means for measuring pressure which appears at the locations ofsaid points and the variation of which is directly related to avariation in level of said points, said means being constituted by atank containing liquid and open to free air and at least one tube whichis attached respectively to said points and the ends of which are infree communication with the tank so as to be continuously filled withsaid liquid, and by pressure gages at least one of said gages beingattached to a lower portion of a wall of said tube at each of saidpoints and means for converting measurement results constituted by anelectronic apparatus for amplification and conversion of the electricalmeasurement data emitted by said gages to data for linear measurement ofvariation in level of said points, and providing an output signal ofsaid data.
 2. A device according to claim 1, wherein the pressuremeasurement means of said device comprises a tank containing liquid andopen to free air, a first tube which is attached respectively to saidpoints and the ends of which are in free communication with the tank soas to be continuously filled with said liquid, and a second tube filledwith air which is attached respectively to said points and the ends ofwhich are open freely to the surrounding atmosphere in proximity to thetank and pressure gages at least one of said gages being attached on oneside to a lower portion of a wall of the liquid-filled tube respectivelyat the locations of the points and on the other side to the air-filledtube, and means for conversion of measurement results constituted by anelectronic apparatus for amplification and conversion of the electricalmeasurement data emitted by said gages to data relating to linearmeasurement of variation in level of said points, and providing anoutput signal of said data.
 3. A device according to claim 2 wherein,within the pressure-measurement means, the air-filled tube has adiameter chosen between 0.3 centimeter and ten centimeters.
 4. A deviceaccording to claim 1, wherein the pressure measurement means comprises atank containing liquid and formed by a cover, a first tube which isattached respectively to the points aforesaid and the ends of which arein free communication with the tank so as to be continuously filled withliquid and a second tube filled with air which is attached respectivelyto said points and the ends of which open through the cover into theclosed portion of the tank enclosure above the free surface of theliquid and pressure gages at least one of said gages being attached onone side to a lower portion of a liquid-filled tube respectively at thelocations of the points and on the other side to the air-filled tube,and means for conversion of measurement results constituted by anelectronic apparatus for amplification and conversion of the electricalmeasurement data emitted by said gages to data relating to linearmeasurement of variation in level of said points, and providing anoutput signal of said data.
 5. A device according to claim 1 wherein,within the pressure-measurement means, the liquid which fills the tankand the tube attached to said tank consists of mercury.
 6. A deviceaccording to claim 5 wherein, within the pressure-measurement means, theliquid-filled tube has a diameter selected between one centimeter andtwo centimeters.
 7. A device according to claim 1 wherein, within thepressure-measurement means, the liquid-filled tube is provided with aliquid circulation pump.
 8. A system for level-setting of a plurality ofpredetermined points of an industrial or scientific installation, suchas that of a synchrotron, equipped with a device for multimeasurement ofthe vertical variation of position of said points according to claim 1,wherein said system comprises an assembly for level compensationinvolving dimensional change by thermal action, said assembly beinginserted between said point or points and its support or their supports.9. A system according to claim 8, wherein the assembly for levelcompensation involving dimensional change by thermal action comprisesthermally expansible elements inserted respectively between the pointsand their respective supports and associated heating elements, and aposition multimeasurement device and a control relay which connects saidheating elements to the corresponding outputs of said position-variationmulti-measurement device and provides said heating elements withautomatic individual supply adjusted in electric power so as todetermine precise compensation for the variation in level of said pointsby means of said expansible elements and to reset said points in one andthe same plane.
 10. A system according to claim 9 wherein, in theassembly for level compensation with dimensional change by thermalaction, the thermally expansible elements are constituted by metallicrods.
 11. A system according to claim 9 wherein, in the assembly forlevel compensation with dimensional change by thermal action, thethermally expansible elements are constituted by jacks which operateunder the action of thermally expansible material.
 12. A systemaccording to claim 9 wherein, in the assembly for level compensationwith dimensional change by thermal action, the thermally expansibleelements and their associated heating elements are isolated by means ofheat-insulating elements.
 13. A system according to claim 9 wherein, inthe assembly for level compensation with dimensional change by thermalaction, the expansible elements and their associated heating elements arisolated from the point supports by means of anti-vibrationheat-insulating elements.
 14. A system according to claim 9 wherein, inthe assembly for level compensation with dimensional change by thermalaction, the expansible elements are equipped with thermal measurementmeans for determining their dimensions.